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Forum Index : Windmills : Servo motor for wind turbine
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piggweed Newbie  Joined: 09/01/2012 Location: United StatesPosts: 29 |
Hello, this is my first time posting. I have a 2kw servo motor, it's 200 vac, 3 ph, 2000 rpm, 14.6 amps wired wye. Would this make a good wind turbine? If so what type of wattage do you think it will produce? All information would be greatly appreciated. |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi piggweed There have been a number of these type motors on the forums over the years and while not ideal they will work, expect around 2 to 300 watts at 24 volts, have a search on the earlier articles on the forum for more information. All the best Bob Foolin Around |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi piggweed Could work, but you need to do some testing first. Have you go access to a lathe, or some way to spin the servo motor at different speeds and measure the voltage, and then again with a load, to measure the current. What we want to know is how much power can we get from it in the 50 to 500rpm range. A 2kw servo would be a big bugger. How heavy is it? Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Bub73 Senior Member  Joined: 10/12/2009 Location: United StatesPosts: 116 |
Those look like pretty good numbers, but nothing is for sure with a servo motor when used as an alternator. You will need too bench test to get an idea of its output. By the tag numbers I'd look for about 10rpm per volt DC it then it depends on your battery bank voltage what the cut in rpm will be. I've found it very important to match the blades to the servo and get them up in clean air. Some more info on bank voltage photos etc may get more input. Bob |
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| piggweed Newbie Joined: 09/01/2012 Location: United StatesPosts: 29 |
I want to thank everybodys reply to my post. I will try to answer all your questions.The servo weighs 14 kg, about 30 lb's. I did some test: with no load @ 800 rpm I get 62 vac, with load it's voltage is 33vac and it outputs 4.2 amps per leg.400rpm 18 vac, 1.7 amps. No load I get 1 vac per 13 rpms. I have two lathes but I am istalling VFD in the one that has varible speed, the other is the one I tested on a old Hardinge with pulley speed change. Thats why I only have a few rpm readings. I am building my first wind turbine, Right now I only have the servo, and I have a 12vdc to 120ac, 4kw inverter that I had for awhile( my bother gets the for free from work, maintance change out and sells to ice cream vender in Fl.). And I have a 3ph rectifier comming. Any info on 12vdc, 24vdc systems would be greatful. I also live on a hill and get realy good winds, 8 to 30 mph about 3/4 of the year. |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
There are many reasons to opt for 24V over 12v, the first for you is the fact that your motor windings have a current rating by design, while up in the wind one can push the boundaries a little but as an example say 10A @ 24V is 240 watts where as 10A @ 12V is 120 Watts. Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
This sounds awfully like an ordinary three phase induction motor. Servos these days mostly run VFDs in forward/reverse for positioning applications. I am not sure that an induction motor without any magnets is ideal for a wind turbine. It is probably producing some output (a few watts only) just from some residual magnetism left in the rotor. That residual magnetism may slowly go away once you start using it as an alternator. Cheers, Tony. |
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97fishmt Regular Member  Joined: 19/04/2010 Location: United StatesPosts: 77 |
450 watts. you should be able to run it at twice the amp rating. It will make a fine 12 volt charger. Build a strong platform and incorporate a furling tail, put a 6' to 8' prop on it and it will last for a long time. Have fun Mike |
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isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Piggweed Go here for some info on your project. there is two pages and some pictures to help out. http://fieldlines.com/board/index.php/topic,146090.0.html Isaiah URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| piggweed Newbie Joined: 09/01/2012 Location: United StatesPosts: 29 |
The motor is a brushless permanent magnet servo, below is a link to the same motor on ebay, you can look at the specs. Isaiah, thanks for the link. That is vary similar to what I am doing. I was looking at Hemi 47" blades, does anybody have any experience with these blades. Thanl you for all your replys. http://www.ebay.com/itm/AC-SERVO-MOTOR-SANYO-MODEL-P60B18200 HXV20-/310365919735?pt=LH_DefaultDomain_0&hash=item48434019f 7 http://www.ebay.com/itm/250969871984?ssPageName=STRK:MEWAX:I T&_trksid=p3984.m1438.l2649 |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi piggweed Fixed those links for your. There is a little Add Hyperlink  button thats does the job.
I have 3 servo motors like that one, though only 1100 watt models. And I turned one into a windmill a few years ago. I was using crappy blades, and results were pretty average, but now I know more and will have another go one day. http://www.thebackshed.com/Windmill/Servo-windmill.asp Those blades are OK, but with a few hand tools you can carve a set of timber blades for less money, and get much better performance. There's a article on the main web site about calving timber blades with a chainsaw! Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| piggweed Newbie Joined: 09/01/2012 Location: United StatesPosts: 29 |
I don't know if I was testing the load correctly, I have a 3000w heat gun and I would tie two of the three legs to the 120vac heat gun, when I got the correct rpm I would turn the heat gun switch on and read the amps from amp meter. Is this a good way to test current output? |
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| 97fishmt Regular Member Joined: 19/04/2010 Location: United StatesPosts: 77 |
If your trying to check it out for charging a battery bank you really need to connect it to a battery through a 3 phase rectifier with the ammeter in between the rectifier and the battery for input current. You spin up the motor and when it reaches battery volts the battery will clamp the voltage. Continuing to spin it faster, the current will flow. This is what you want to measure. So if you hook up a 12 volt battery and can get it up to 15 volts and are able to push 30 amps into it with your set up, that's 450 watts. If you can get more without the motor getting hot then see what you can get. It sure helps if you can track rpm to figure out what kind of blades to put on it. I've been using servo motors for wind turbines for around 15 years and scattering machines around my community to the neighbors and they are all still in service with no issues. Mike |
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| piggweed Newbie Joined: 09/01/2012 Location: United StatesPosts: 29 |
I am waiting on my 3ph rectifier, I should have in a week. I just got my vsl lathe running so now I can dial it within 1 or 2 rpm's, from 50 to 2500 rpm. I do have a Fluke dc clamp on ampmeter. I will test the dc when the rectifier get here. At 1000 rpms I am putting out 7.5 amps @ 1000 rpm ( 2.5 amps x 3 legs = 7.5 amps x 120vac = 900 watts ). Would that give me 37.5 amps @ 24 vdc? Can you or anybody else recommend a good charge controller? |
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| 97fishmt Regular Member Joined: 19/04/2010 Location: United StatesPosts: 77 |
I've been using two c-40's for a long time. They are a little slow to dump. I hear the tristar units work real well. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
O/k I stand corrected. I have repaired literally dozens of servo drive systems that used ordinary three phase induction motors. I was unaware that synchronous three phase motors were sometimes used in this application. Cheers, Tony. |
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| isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Piggweed http://www.thebackshed.com/forum/forum_posts.asp?TID=4488&PN =1 this post is also a servo motor, the pictures dont show much of the motor but adding the blade extenders made a big difference in the output the bottom two are of the blades turning at night with a led truck clearance light shining on them. It makes them look like they are on fire. welcome aboard there are some of us here that like servo motors and we have some ecm's we have worked with. a lot of info here just ask some bull dung also Isaiah URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Piggweed, Unfortunately, you have a problem with your servo motor in that it will have relatively high resistance windings, and this will limit its output into a low voltage system - particularly at typical turbine speeds which will be well below its design speed of 2,000 rpm. It would be possible to drive the servo through some sort of step up arrangement, but this would have its own friction losses. The basic problem is that the diameter of the rotor of the servo will be too small to serve as a good direct driven wind generator. Purpose designed wind generator alternators are necessarily of a larger diameter, in order to be useful at lower speeds, and would have much lower resistance windings. The other awkward problem is that the more power that you try to get out of your servo for a given wind speed, the bigger the turbine diameter you will need, and the slower the whole system will turn. By all means experiment with your servo, which will probably be able to put some amount of charge into a battery, but you would be better to get a more suitable alternator if you intend to put a major effort into it, Regards Don B |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Don is right about the safe maximum current. The rating plate will have a maximum continuous current rating when used fully loaded as a servo motor. That would also set the same safe maximum current when used as an alternator. It has to do with temperature rise in the windings, which will be the same in both applications for similar current through the windings. Cheers, Tony. |
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| isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
it's 200 vac, 3 ph, 2000 rpm, motor 2000 rpm's divided by 200 volts = 10 rpm per volt x 15 gives you a 12 volt cut in speed of 150 rpm's which this motor should do for many years with no problems. '  I would expect 7.5 amps minimum out of it and maybe up around 43 amps.
The only thing I would check is the front bearing and see that it is a sealed bearing and not just a shielded on as you may get some water in a shielded bearing. I think id use a blade like the Windy Nation 80 inch wind grabber. We had one of those blade sets up all summer on a servo with no problems. It looks to me piggweed has a nice motor for his first mill.!! '
Isaiah URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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